1. Field of the Invention
The present invention relates to a method for forming a carbon-metal composite material for a heat sink, and a heat sink which has at least one shaped body.
2. Background
WO 2010/057236 describes a heat sink and a method of producing the heat sink. The heat sink has a base body comprising an insertion body that consists of a carbon-metal composite material and that is spaced away from a positioning surface for positioning a component to be cooled, e.g. a laser diode. Silver-diamond, copper-diamond and aluminium-diamond, in particular, are specified as carbon-metal composite materials.
The insertion body can be produced by filling a receptacle with a carbon phase and a metallic phase, the metallic phase in the (molten) liquid state entering the receptacle in order to infiltrate the carbon phase. Both unpressurised processes and processes with pressure support, e.g. a GPI process (Gas Pressure Infiltration Process), can be used for the purposes of infiltration. Irrespective hereof, hot pressing of the insertion body is alternatively described as a further production method.
Owing to the low quality of the upper surface of the insertion body produced in the way described above and the fact that post-processing of the insertion body, for example by polishing, is possible only at considerable expense, it is suggested that the insertion body, after it has been received in the base body, be applied at a distance from the positioning surface for application of the component and covered, for example, with a solder layer.
U.S. Pat. No. 5,273,790 discloses a method for consolidating synthetic diamonds or diamond composite materials that can be used, inter alia, for cooling electronic components. For this purpose, particles of diamond or other materials are infiltrated with diamond material having a high thermal conductivity using a CVD method. A volume of the consolidated diamond material or diamond composite material can be structured in layers by infiltrating a respective layer or preform of diamond or other materials with diamond material using a CVD method.
US 2007/0071907 describes an article or body which has an iron-containing substrate and a wear-resistant layer that consists of a composite material. The composite material has diamond particles in a metal matrix. In order to form the composite material, a particle mixture of diamond particles and metal particles is applied to the iron-containing substrate and the mixture is heated in a non-reactive atmosphere using a laser beam in order to fuse the metal particles so that they bond with the substrate and with the diamond particles to the wear-resistant layer. In order to prevent the diamond particles being damaged by the laser radiation, a material having a melting point of between 400 and 900° C., in particular silver or copper, is recommended as the metallic matrix material.